Matic telephone exchange



(No Model.) 7 3 Sheets-Sheet 1.

A. E. KEITH, F. A. LUNDQUIST & J. 86 G. J. ERIOKSO'N. ELEOTRIGALEXCHANGE.

No. 540,168, Patented May 28, 1895.

HII! WITNESSES: lNVENTORS '8. Jdwr (No Model.) 3 Sheets-Sheet 2.

A. E. KEITH, PQA. LUNDQUIST & J. & 0. J. ERIOKSO N. ELECTRICAL EXCHANGE.

No. 540,168. Patented May 28, 1895.

WITNESSES: INVENTORS 621 6a,. 5. 7% W yflga {jka/t/a/g g 3 SheetsSheet3. A E. KEITH, F. A. LUNDQUIST & J. -& G. J. ERIOKSON.

(No Model.)

ELECTRICAL EXCHANGE.

No. 540,168. Patented May 28, 1895.

GROUND lVETOS NN R a 4 uni :1

WIT ESSES; 25 M g M M UNITED STATES PATENT OFFICE.

ALEXANDER E. KEITH, FRANK A. LUNDQUIST, JOHN ERIOKSON, AND OH ARLES J.ERICKSON, OF CHICAGO, ILLINOIS, ASSIGNORS TO THE STROWGER AUTO- MATICTELEPHONE EXCHANGE, OF SAME PLACE.

ELECTRICA'L EXCHANGE;-

SPECIFICATION forming part of Letters Patent No. 540,168, dated May 28,1895.

Application filed November 7,1894. Serial No. 528,165. (No inodel.)

To allwhom it may concern.-

Be it known that we, ALEXANDER E. KEITH, FRANK A. LUNDoUIsr, JOHNERIOKSON, and CHARLES J. ERICKSON, citizens of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a new anduseful Electrical Exchange, of which tricallyinterconnected switch arms in each:

exchange, which are operated simultaneously, and the several exchangesof any given system are electrically interconnected by a new syszo ternof wiring whereby the connecting wires serve as contacts with which theswitch arm in each exchange may be placed in direct electricalcommunication without the necessity of the usual contacts and the legwires for establishing communication between such contacts and theexchange interconnecting wires; and still another object is to provide aspecial arrangement of the exchange interconnecting wires ingroups often, there being 0 one switch-arm for each group and mechanism wherebyeach switch-arm may contact any one wire of its particular group, andby, which but one of the several switch arms in each exchange is placedin electrical 0011111111". nication with but one wire at a time of theseveral groups, substantially as hereinafter described and illustratedin the accompanying drawings, in which Figure 1 is a side elevation.Fig. 2 is a plan 0 view. Figs. 3 and 4. are side and end elevations of aportion of one end of the principal,

operative parts. Fig. 5 is a diagram showing a system of interconnectingexchange wires with three exchanges connected therewith.

Similar numerals and letters refer to like parts throughout the severalviews.

The exchange comprises a switchboard having a series of rows of contactpoints mounted thereon, the contact poirits of each row beingelectrically.connected, in combination with a series of connectorsarranged for co-operation with the switchboard, and means for operatingthe connectors to interconnect the wires of the system.

A very desirable form of switch-board is made by arranging a series ofwires parallel with each other in such a position that each connector iscapable of making and breaking electrical connection with each and everyone of them. One form of connector is shown in the drawings and consistsof a revoluble shaft 2, capable of a rotary and a longitudinal movement,in two directions, the shaft having secured thereto, and in electricalcommunication therewith, a plurality of electrically interconnectedswitch-arms, as 3, 4t, 5, 6, and 7 whose outer free ends, by themovements of the shafts 2,are capable of contacting the series ofinterconnecting contact points or wires Sor anyother means of conductingelectricity. 7o Shaft 2 is mounted in a hearing at one end, and at theother end passes through a miter wheel 9 whichis mounted in the top of abear: ing 10 to permit rotation only, the shaft being capable ofrotation with the miter wheel and also of a longitudinal movementtherethrough, being heldto revolve with the wheel by the long spline 11.The shaft is caused to rotate, step by step, by virtue of electro magnet12, or any other means, operating bell crank lever 13, whose pawl 14engages the teeth of ratchet wheel 15, which ratchet Wheel is mounted torotate on a stud pin 16 with miter wheel 17, this pin being secured atone end to a stand ard' 18 from base plate 1, the two miter wheels beingin engagement as shown so that, any rotary movement given to ratchetwheel 15 is transmitted to the shaft. There is a helical spring 19, Fig.2, which revolves the ratchet wheel and the bevel wheelsin an oppositedirection to that imparted by the action of pawl 14. There is a stop pin20 projecting outwardly from ratchet wheel 15 which strikes against abent wire 21, and limits the motion imparted to it by a spring 19, andthere is a 5 projection 22 from standard 23 against which ,the stop pinstrikes to limit the motion imparted by the action of pawl 14, theratchet wheel never completing a whole revolution. Detent 24 when inengagement with the teeth I00 of the ratchet wheel serves to hold itafter the thrusts of pawl 14.

At the inside end of shaft 2 is an enlargement 25 which is fitted with aseries of circumferential grooves which are engaged by a cog wheel 26which is mounted, together with ratchet wheels 27 and 28, upon a studpin 29, which is secured at one end to a stout standard 30 projectingupward from base plate 1; both standards 18 and 30 being shown in planview in Fig. 2, but in broken lines in Fig. 1.

Cog wheel 26 is made to rotate step by step in one direction by virtueof electro magnet 31, or any other means, operating bell crank lever 32when pawl 33 is in engagement with ratchet wheel 27, ratchet wheel 28serving as a stop wheel when engaged by the outer end 32' of bell cranklever 32.

Helical spring 34 serves to operate cog wheel 26 in the oppositedirection to that just described.

Figs. 3 and 4 plainly show a longitudinal groove 35 cut in theenlargement 25 of'shaft 2 which is for the purpose of receiving the endof a stop 35 which, when shaft 2 is revolved, may pass into any of thecircumferential grooves and hold the shaft in position longitudinallyuntil it has revolved backwardly to the position shown in Figs. 1 and 2,with all the switch arms 3, 4, 5, 6, and 7 lifted from the wires 8.

The relative arrangement of the mechanism for rotating shaft 2 and forimparting a longitudinal motion thereto is such that, the shaft mustalways be in position shown in Figs. 1 and 2 before it can be movedlongitudinally.

In Fig. 1 are shown bent arms 36 and 37 which have one end attached tothe actuating pawls, while the other end contacts with the base plate tothrow the pawls out of engagement with the ratchet wheels, when thelevers are in the initial position shown. Detent 38 engages with ratchetwheel 28 and is also hooked to detent 24 by means of a cross rod 24,Fig. 2, so that by lifting detent 38, detent lever 13, near pawl 14, andthe outer end of.

this cross rod passes in under lifter 37 of pawl 33 so that, wheneverpawl 13 is raised, pawl 33 is thrown backuntil pin 33, at the top endthereof, is in line with downward projection 39 of detent 38, when iflever-32 is lifted pin 33 will strike the projection and lift detent 38together with detent 24 clear of the ratchets. tent 38 is an arm 41which has the lower end 42 bent at a right angle to project laterallysufficiently to pass under bell crank lever 13, Fig. 2, and when theseveral parts are at the initial position, as shown in the drawings,with all the pawls and detents raised, the end 42 has a position at theleft hand side of a pin 43, as shown in the solid lines, which projectsPendent from and firmly secured to de-' downwardly from lever 13, thispin serving to hold detents 38 and 24 in the raised position, shown inthe act of release, which permits all of the operative parts to bereturned to the initial position by the action of helical springs 19 and34.

In Fig. 2 is shown five groups of exchange inter-connecting wires,indicated by A, B, C, D, and E between the dotted lines, each groupcomprising ten wires, and in order to illust'rate one manner ofoperating this exchange, we will say that the wires 8 in each group arenumbered and connected with an exchange having a corresponding number,as for instance by a wire or connector J, leading from one of the wires,and that it is desired to connect shaft 2 with the first wire, at theleft hand side of Figs. 1 and 2, then, the first act is to operate lever13, which will cause pawl 14 to turn ratchet wheel 15 and shaft 2 theamount of one ratchet notch, lever 13 lifting high enough to permit theweight of detents 24 and 38 to carry the end 42 of arm 41 to the rear ofpin 43, to position shown in broken lines in Fig. 1, when detent 38 willengage ratchet wheel 27, and detent 24 engage ratchet wheel 15, afterwhich, if another movementis given to pawl 14, switch-arm 3 will beturned with shaft 2 around in the direction indicated by arrow F, andthe free end of the switch arm be placed in contact with the first wire8 in the first group A, with detent 24 holding the switch-arm in thatposition against the tension of spring 19, when it is obvious that acurrent of electricity may be sent from shaft 2 into and through saidfirst wire. To return the operative parts to the initial again, lever 13is first operated, and held in the operated position, which causes pawl33 to be forced back, as hereinbefore described, under projections 39,when lever 32 is operated, causing detents 38 and the attached detent 24to be lifted from their ratchets. The levers 13 and 32 are successivelyreleased and the ICC springs 19 and 34 cause a backward movement of theoperative parts to the initial position.

It is obvious that by the step by step movement shaft 2 may be rotatedin the direction of arrow F so that each of the switch arms 3, 4, 5, 6,and 7 will successively contact the first wire of each group, beginningwith series A at the left hand side of Fig. 2.

From the initial position, to cause the switch arms to contact the otherwires of the groups, the longitudinal movement of shaft 2 is necessary,which is attained by one upward movement of pawl 14 to permit thedetents 38 and 24 to fall into engagement with the ratchet wheel, afterwhich lever 32 is operated causing pawl 33 to actuate ratchet wheel 27and move shaft 2 longitudinallyin the direction of arrow G, step bystep, pawl 33 being actuated as many times as is necessary to find thewire in each group desired, after which contact may be had with saidwire, by actuating pawl 14 to cause some designated switch arm 3, 4, 5,6, or 7 to contact the desired wire, as before described, each step orlongitudinal movement of the shaft being equal to the distance fromcenter to center of the wires 8 in each group.

Whether shaft 2 is rotated tov cause the switch arms to contact thefirst wire of each group, or whether a longitudinal and a rotarymovement, successively, are given the shaft by which the switch arms maycontact some other wire of each group, the release by which the severalparts return to the initial positionis accomplished first by spring 19,and then by spring 34 after lifting detents 24 and 38 as described, butthe backward rotary movement of the shaft 2 first takes place first onaccount of the engagement of stop 35' in one of the grooves of theenlargement 25, which throws all the switch arms clear of the wires, butas soon as the stop is in longitudinal groove 35, spring 34 is free toslide shaft 2 longitudinally to the initial position shown in thedrawings.

It will be understood that after shaft 2 has been turned forwardlysufficiently to cause any one of the switch arms to contact a wire, anylongitudinal movement of the shaft in either direction cannot takeplace, on account of the enlargement of stop 35', as before indicated.

It is obvious that it is not always necessary for the interconnectingwires 8 to be directly contacted by the switch arms, for any form ofcontact in electrical connection with these wires may be used.

In Fig. 5, three groups of ten wires each, and three exchanges, K, L,and M are shown in diagram, each exchange being directly connected bysome one of the wires J to but one of the wires 8 which are disposedusually parallel and in horizontal plane at the rear of all theexchanges in a given system so that, although each exchange has but oneof the wires 8, such as wires 101, 102, 103 respectively, directlyconnected thereto, each of the exchanges may be placed in electricalcom- 'munication with any other wire of the several groups by means ofthe plurality of switch arms and shaft described, each of which switcharms contact only the ten 'wires which comprise its particular group.The switch arms are disposed on the shaft radially, each at a 'diiferentangle to the other so that, but one switch arm of the same exchange isin con In exchanges tact with a wire at one time. of this class it isusual to insulate each of the exchanges from ground and from each other.

ally in electrical communication with the switch arms through the frameand shaft 2,

although the switch arms may each be insulated from the shaft and be inelectrical communication with the line wire in various Ways,

as is obvious to those skilled in the art to which this inventionbelongs, as above described.

As above described, the exchange can be operated manually and can besubstituted for the mechanism used at present in the various kinds ofexchanges, or it may be operated electrically and thereby be used forany of the automatic exchanges in use, although we wish it to bedistinctly understood that we do not limit ourselves to any particularmethod of using it, our invention residing broadly,in the plurality ofwires or contact 1 points and the plurality of shafts and switch arms orconnecto rs, each of which is adapted to be moved into or out ofengagement with each of the contact points. 7 t V For the purpose ofexplaining how our invention may be used electrically, or with anautomatic system, we will now explain one way, although it is evidentthat other ways may be employed.

Referring more particularly to Figs. 1 and 5, 12 and 31 indicate twomagnets, the armature of one of which, 12, is connected with the lever13, and is adapted to rotate the shaft, and the armature of the otherone, 31, is connected with the lever 32, and is adapted to move theshaft longitudinally. Each of the magnets is connected with a battery orother source of electrical energy at one terminal through the wire N,and one of them,

12, is permanently connected with a suitable telephone and key boardbyawire P, and the other one, 31, is detachably connected with the shaft2 through the wire Q which connects with the spring 50. The telephoneand key board is also connected with the shaft through the wire Rthrough-the frame of the machine. The spring 50 is insulated from thebase at one end and is adaptedto be engaged by the pin 20 when the wheel15 has been rotated one step and to be disengaged when the wheel hasbeen rotated any farther. The bent wire 21 is permanently connectedvwith any one of the wires 8 through its respective connecting wire J,and is normally in electrical connection with the shaft 2, through thepin 20, but as soon as the wheel 15 has been rotated one step, theconnection betweenthe shaft and the wire J is broken.

It willthus be seen that the first step made by the wheel 15 breaks thecircuit between the shaft and the wire J, thereby preventing outsideinterference and at the same time establishing a circuit through themagnet 31 whereby the shaft may be moved longitudinally if desired.

Referring to Fig. 5 in which the wires or contact points 8 are arrangedin three groups,

numbered from 101 to 191; 102 to 192, and

103 to 193 respectively, each exchange is provided with a shaft havingthree switch arms,

each one of which isadapted to be moved into and outof contact with anyone of the wires of its respective series. Two of the exchanges K and L,are shown in their normal position, while the exchange M is shown asbeing in communication with exchange L. In the exchangesK and Lall theswitch arms on the shaft 2 are out of contact with the wires 8, while inthe other exchange M, the end switch arms are out of contact, but one ofthe middle ones, T, is shown in contact with wire 102, therebyestablishing communication through the wire J with exchange L. Ifcommunication had been desired by M with exchange K it would only havebeen necessary to have rotated the shaft 2,an0ther step, which wouldhave thrown the middle switch arm out of contact and the end one nextthe exchange into contact with the wire 103.

In order to operate the magnet andother mechanism as above described,resort may be had to any suitablev means, as for instance a key boardhaving four keys, H, T, U, and R, in which each operation of the keys Hor U will close the circuit through wire P, magnet 12, and wire N andwill rotate the shaft one step, and cause pin 20 on ratchet wheel 15 tocontact spring 50 when each operation of the key T will close thecircuit through the wire R, and the frame and mechanism to pin 20,spring 50, magnet 31 and wire N, and will move the shaft longitudinallyone step. The key H might be dispensed with by operating the key U oncebefore trying to place the switch in connection with any of the wires,as one operation of it will operate the shaft one step which will breakthe connection with the outside wires and willalso place the shaft inposition to be moved longitudinally, if desired, after which the key Ucan be operated as many times as is necessary to cause the proper switcharm to engage with the desired wire; but we prefer to use the key H forrotating the shaft the first step, and then not numbering any of thewires less than 100 asthis prevents any confusion of operating any ofthe keys the second time, after any of the other keys have beenoperated. For instance, if a subscriber wants tocall 143, he firstpresses the key H which indicates the hundreds and also rotates theshaft one step. He then operates the key T four times which carries theshaft four stops, after which he operates the U key three times whichmakes the third switch arm contact with its wire. To release themechanism, the key R is pressed down which will close the circuitsthrough both wires and magnets and the wire N and will permit all theparts to assume their normal positions, as heretofore explained for themanual operation of the levers 13 and 32.

Having thus described our invention, we claim- 1. An automaticelectrical exchange comprising the combination of a switch-board havingmounted thereon a series of rows of contact points, the contact pointsof a row being in electrical connection, a series of connectors arrangedfor co-operation with the switch-board, a series of, subscribers linesconnected with the respective connectors and through them, and throughthem only, to the contacts of the switch-board, and means for operatingthe connectors to interconnect said lines, substantially as set forth. 1

2. An automatic electrical exchange comprising the combination with aswitch-board provided with a series of rows of electricallyinterconnected contact points, a series of connectors arranged toco-operate therewith, each connector being normally connected with butone of the rows of contact points, and means for breaking the normalconnection as soon as the connector is operated for making connectionwith any of the rows whereby communication between any two of thesubscribers is entirely secret from the others, substantially. asdescribed.

3. An automatic electrical exchange comprising the combination of aflat, continuous, non-sectional switch-board having mounted thereon aseries of rows of electrically interconnected contact points, a seriesof connectors arranged parallel with the switchboard, and means foroperating the connectors to in terconnect the wires of the system,substantially as set forth.

4:. An automatic electrical exchange comprising the combination of afiat, continuous, non-sectional switch-board having parallel wiresmounted thereon, a series of rotatable conductors arranged transverselywith the wires, each conductor being provided with means for making andbreaking electrical contact with each and every one of the wires, andmeans for operating the connectors, substantially as set forth.

5. 'An automatic electrical exchange comprising the combination with aflat switchboard having parallel wires mounted thereon, a-series oflongitudinally movable, rotatable conductors arranged transversely withthe wires, said conductors being each provided with a series of spirallyarranged arms, the free ends of the arms being adapted to be moved intoand out of electrical contact with the wires, and means for operatingthe conductors, substantially as set forth.

6. An automatic electrical exchange comprising the combination of a flatswitch-board having parallel wires mounted thereon, a series oflongitudinally movable, rotatable conductors arranged transversely withthe wires, each conductor being provided with laterally projecting arms,the free end of said arms being adapted to be moved into and out ofcontact-with the wires, and means for preventing the longitudinalmovement of the conductor when any arm is in contact with its respectivewire, and means for operating the conduc' tors, substantially as setforth.

7. An automatic electrical exchange comprising the combination of aswitch-board provided with parallel wires moun tedthereon, saidwiresbeing arranged in groups, a series of longitudinally movable, rotatableconnectors arranged transversely with the wires,

each connector being provided with a series of radially projecting arms,one for each group, and means for moving each arm of the prising thecombination of a switch-board provided with parallel wires mon ntedthereon, a series of longitudinally movable, rotatable connectorsarranged transversely with the wires, each connector being rotatable atall times and normally in electrical connection with but one of thewires, and means for mov; ing each connector step by step, theelectrical connection being broken at the first rotary step and thelongitudinal movement being possible only after the first rotary step,substantially as set forth.

9. An automatic electrical exchange comprising the combination with aswitch-board provided with parallel wires, a series of connectorsarranged transversely with the wires, each connector being provided withmeans for making electrical connection with the wires bya rotary and alongitudinal movement, two levers for operating the connectors, one ofwhich controls the rotary movement, and the other the longitudinalmovement, substantially as set forth.

10. An automatic electrical exchange comprising the combination with aswitch-board provided with parallel wires, a series of connectorsarranged transversely with the wires, each connector being provided withmeans for making electrical connections with the wires by a rotary and alongitudinal movement, of two levers for operating each conductor, oneof which controls the rotary movement and the other the longitudinalmovement, a magnet for each lever, and means under the control of thesubscriber for placing the rotary magnet in the circuit at any time andthe longitudinal magnet only after the rotary magnet has been operatedone time, substantially as set forth.

In testimony that we claim the foregoing we have hereunto set our handsthis 30th day of October, 1894:, in the presence of witnesses.

ALEXANDER E. KEITH. FRANK A. LUNDQUIST. JOHN ERICKSON. CHARLES J.ERIGKSON. Witnesses: THOMAS F. SHERIDAN,

EPH RAIM BANNING.

